| For most in-space operations (ISO), e.g., assembly, repair, refueling, the target location and its orbit parameters are known a priori. For instance in the case of an assembly mission, the general location of the construction site and the parts depot are known parameters in mission planning. Utilizing this known information, we propose a novel approach to collision-free operations for a heterogeneous team of spacecraft robots performing the ISO mission based on artificial potential function (APF) guidance.; In order to utilize APF guidance two prominent deficiencies of APF methodologies need to be circumvented: premature termination due to local minima in the operational space and suboptimal performance. It is widely known that utilization of harmonic potential functions eliminates the introduction of local minima in the operational space; thus we employ harmonic functions to conquer the first of the aforementioned deficiencies. In order to surmount the suboptimal performance, we propose the use of a sum of harmonic function primitives (simple functions such as sinks and vortices in the hydrodynamic analog) to shape the velocity field of the operational space to harness the underlying dynamics of the system (i.e., orbit mechanics). Furthermore, given the location and orbit parameters of the target site, a random heuristic search algorithm can be employed to optimize the velocity field shaping for maximizing the performance gains achieved from harnessing these underlying dynamics. |
